Book backbone structure with concealed rivet means and method of making same



Dec. 4, 1956 E. c. RANKIN 2,772,427

BOOK BACKBQNE STRUCTURE WITH CONCEALED RIVET MEANS AND METHOD OF MAKING SAME Filed Jan. 18, 1952 Infinforx Edward 6'. Ranki United States Patent BOOK BACKBONE STRUCTURE WITH CON- CEALED RIVET MEANS AND METHOD OF MAKING SAME Edward Charles Rankin, Oak Park, 11]., assignor to Brock & Rankin, Inc., Chicago, 111., a corporation of Illinois Application January 18, 1952, Serial No. 267,138

13 Claims. (Cl. 112) This invention pertains to the bookbinding arts, and the disclosure provides in its principal features a novel backbone structure and a method for making such structures for use in books generally, and especially for so-called loose-leaf binders of a type having a ring-binder mechanism or the like rivited onto the backbone.

More specifically, the invention affords as one of its principal features, a backbone structure fabricated from binders board according to a method of manufacture which produces a remarkable increase in strength at a cost which is negligible in view of the advantages gained and the superiority of the product as to durability, appearance, and enhanced utility.

Still more particularly, the invention provides an improved method of making a certain type of loose-leaf book case which utilizes existing machinery and processes up to the point of the improvement, to form the roughed blank or flat casing in the usual manner, and thereafter adds certain steps and structural modifications to provide a casing having a much stronger backbone with a novel concealed rivet means.

A further object of the invention is to improve the manufacture of paperboard book and binder casings to overcome the inherent structural weakness of the conventional rounded backbone made of binders board and similar fibrous boards of the non-impregnated class, by making the backbone of two pre-formed backbone strips each of half the weight of the companion cover boards, and joined by a hard-setting glue applied after the backbone pieces have been pre-rounded.

Additional aspects of novelty and utility relate to details of the structure and the method for making it, which will appear as the following description proceeds in view of the annexed drawing in which:

Fig. 1 is an inside plan view of a partially fabricated casing or binder;

Fig. 2 is a sectional detail, to enlarged scale, taken along lines 22 of Fig. 1;

Fig. 3 is a perspective view of a pre-formed sister backer taken to the approximate scale of Fig. 1;

Fig. 3A is a view similar to Fig. 3, but showing the pre-formed sister backbone turned .over and glue applied thereto;

Fig. 4 is an enlarged cross-sectional detail of the backbone portion of the casing of Fig. 2 after the first rounding operation;

Fig. 5 is a view similar to Fig. 4 showing the preformed sister backbone secured in position on the outer backbone with blind rivets applied;

Fig. 6 is a view similar to that of Fig. 5 but showing the cover cloth applied as in the finished casing;

Fig. 7 is a perspective to reduced scale of the finished casing of Fig. 6 in open condition;

Fig. 8 is a magnified cross-sectional detail of the backbone and hinge region of the casing with the covers in a closed condition;

Fig. 9 is a fragmentary perspective of a modified backbone strip.

"ice

According to conventional practices, the manufacture of a certain type of casing or binding, particularly for loose-leaf types of binder, begins with the preparation of a flat case, such as shown in Fig. 1, and which consists of a pair of cover boards 1t and 11, flanking a backbone piece 12, and all joined by an outer facing cloth 1 iglued to the outer faces of the boards, with the marginal edges or the cloth turned over onto the inner faces thereof, as at 14A, there being a narrow unattached hinge area 15 of this cloth between the confronting edges of the covers and the backbone strip.

The manufactured casing, when rough finished, is flat, as in the constructions shown in Figs. 1 and 2, such casings being finished in the sense that they constitute a completed subassembly, which may be, and generally is, subjected to further operations, such as rounding of the backbone, applying inner liner cloths or liner sheets, and attaching one or another type of loose-leaf binding device to the inside face of the backbone, etc. Since such further operation may include one or all of the additional operations named, the fiat covers are regarded as manufactured or finished cases, and in mass production are generally turned out by machines which feed the paperboard blanks onto the cloth and apply the necessary glue, pressures and heat, and also turn-in the margins of the cover cloth. Rounding is generally a separate machine operation.

Customarily, the covers 10 and 11 and the backbone piece 12 are cut from binders board, which is a relatively heavy paper board made much in the same way as ordinary paper, that is to say, by settling or laying down pulp fibers in a matte until the desired thickness and weight is attained, and then pressing and drying the matte to produce a substantially rigid fibrous board.

In making such casings according to prior practices, the three pieces 10, 11, and 12, are customarily of the same weight or thickness, all three pieces commonly being cut from IOO-point board.

Usually the finished casing, such as shown in Pig. 1, will require a rounded backbone, and it is to this particular type of binding that the present disclosures especially pertain in part.

Accordingly, the casing shown in Fig. 1 would be subjected to a rounding process 'by passage through a known type of rounder, which imparts the desired curvature to the backbone strip, so that the backbone 12A will then have the curvature depicted to magnified scale in Fig. 4.

At this juncture it is important to emphasize that the initial steps in making a finished blank casing according to both the old method and the new method disclosed herein are the same with one significant exception, namely, that whereas in the old method the weight or thickness of binders board used for all three pieces 10, 11, and 12. i. e. the two covers and the backbone strip, is the same, usually IOU-point board, the new method prescribes a departure in that the IOU-point thickness of each of the two cover boards is still kept equal, but the thickness of the backbone blank is decreased about one-half, i. e. to 50-point stock, these differences being portrayed in Figs. 2 and 4.

The new method and structure may therefore be said to start with the preparation of a blank case consisting of a pair of flat cover boards and a flat backbone strip of about one-half the thickness of the covers, and all hingedly joined by a jacket of bookbinders cloth. Such a half-thickness backbone strip is designated herein as the outer backbone.

The fiat case is passed through the usual rounding machine, which curves the outer backbone until it has the appearance of the piece 12A in Fig. 4. The backbone will thereafter tend to spring somewhat out of shape and assume its secondary residual curvature.

According to the next step of the imp oved method, a sister or inner backbone 13 is blanked out of halfweight (i. e. 50 pt.) binders board and pre-formed, by giving it a complementary curvature as indicated at 13A in Pig. 3, such curvature being imparted by a machine (not shown) employing suitable dies under considerable pressure.

If the completed binder is to be equipped with a riveted ring binding mechanism of conventional type, then the blank for the piece 13 is also supplied with a pair of rivet punches 16.

Where such rivet punches 16 are included, the outer or convex side of the sister backbone is provided with radial grooves 16A radiating from the punches 16 (as in Fig. 3A), but not cut entirely through the board, for reasons to appear.

In the next step of the method, the pre-formed sister backbone 13 has its outer or convex surface supplied with a coating of glue 163, this glue being of a hard-setting variety, such as bookbiuders hide glue, as distinguished from flexible glues.

If the riveted structure is required, the rivets 17 are dropped into punches 16 with their heads 17A overlying the radial slots 16A, said rivet heads being thinwalled and slightly curved to conform to the meeting curvature of the outer and inner backbones.

At this stage, and while the glue is adequately tacky, the coated pre-formed sister backbone is pressed home into nested interfit with the inner concave face of the outer backbone, and the glue allowed or caused to set. In the production process, heated dies (not shown) are preferably used for this purpose to hasten the setting and drying process.

As depicted in Fig. 5, the two longitudinal or hingemargin edges 13X of the sister backbone are preferably caused to project beyond the correspondng edges of the outer backbone to substantially abut the corresponding hinge margins X, 11X of the cover boards to produce an abutting hinge juncture when the covers are closed. This construction produces a better appearing hinge because it tends to partially fill-in some of the otherwise vacant area along the inside of the hinge margins, and becomes of peculiar importance when the binders are packed in cases for shipping, especially where the book contents or leaves are bound-in.

Customarily such binders are packed in a vertical position, as shown in Fig. 8 (sometimes in alternation with one backbone uppermost and the next down, etc.), so that the weight of the bound leaves hangs from or rests upon, the backbone and represents a considerable load on the arched backbone structure, suflicient to cause extensive damage resulting in flattened or cracked backbones as a consequence of dropping and throwing of the shipping containers.

In the position of Fig. 8, it will be apparent that the two terminal or hinge edges of the backbone arch can rest closely upon the upper edges of the cover boards,

- so that the latter, and not the hinge cloth, mainly support the loaded backbone. This construction, in combination with the stronger composite backbone, practically eliminates damage from the causes alluded to.

The casing is completed by gluing-in the usual cloth backbone liner 13 over the inner face of the sister backbone, the liner extending a short distance onto each cover board so as to underly the usual paper side liners or sheets 19 which are then glued-in to dress the inside of the covers.

The binder casing is shown in completed condition in Fig. 7, so far as the novel structures and methods of the disclosure are concerned. However, the finished binder will subsequently be supplied with some form of looseleaf binding device, such as the well-known snap-ring mechanisms, consisting of a metal base with ring jaws on which the leaves are hung (not shown). Customarily the metal secured to the base strip of such a binding de-' It is important to observe that such ring-binderap pendages and the metal base strips thereof have commonly been relied upon heretofore to reinforce the backbones and prevent to some extent injury thereto with respect to flattening and cracking of the backbone along the ends or hinge margins, etc. Without such reinforcement the old paper back backbones are extremely vulnerable to flattening and fracture; and in general such backbones are so inherently weak that they have a limited life and can be flattened or cracked fiat easily by abuse even with I a metal strip secured thereto.

The objectionable peculiarities of the old type backbone are well-known in the trade, but there have not been any acceptable or commercially feasible remedies for the problem until the advent of the present improvements, it being essential to produce such binders at the very lowest cost in order that there may be any commerce in them at all.

Ring binder attachments have been produced with especially rounded wide backs as a reinforcing means for the old style paperboard backs, but the cost of such specialties is prohibitive for the bulk of the trade in t these commodities.

The backbone structure made according to the methods disclosed herein is characterized mainly by its greatly increased strength, retention of curvature, and rigidity.

These advantages are attained at a relatively insignificant increase in manufacturing costs of the reason, among others, that all existing machinery and procedures are retained in preparing the rough case blank.

Reinforced backbone assemblies have been proposed in the old art, and a variety of composite constructions have been devised for purposes of decorative embellishment and in an effort to overcome the inherent weakness of the rounded paperboard back; but those of the latter type having practical merit are either too costly or adapted only to use with a difierent technique of binding. The present developments are of particular significance in that they apply especially to the manufacture and mass production of inexpensive binders from common binders board. Being of matted fibrous character, this board does not lend itself to bending without a disturbance of the fibre bond, and naturally tends to retain its original flat matted shape, owing to the nature of the orientation and bonding of the fibres in the matte; and even after being subjected to pressure in the rounding dies the board will tend to spring back somewhat to its original condition.

Thus, when binders board is given a substantial curvature, as for rounded backbones, some of the fibres are disturbed, or ruptured, and the board at once becomes potentially, if not immediately, Weaker, depending upon.

the lateral edges, at head and foot, of the sister strip..13;.i

may be colored to match the cover cloth if desired for some classes of binding.

While it is possible to cover both backbones by the cloth turn-in, as at 14A, such a step adds a cost which is prohibitive in most cases and interferes with the established mass production of blank cases.

Another feature of the improvement affords at one and the same time a further reinforcing means for the backbone structure, as well as a means for dressing the lateral edges of the sister strip. As depicted in Fig. 9, the lateral edges (head and foot) of the sister strip 13B are provided with a narrow band of cambric or like lightweight cloth of suitable color, folded around the edge in the manner of the foot band 13C (the head band being identical and therefore not illustrated).

The end bands 13C serve to dress the exposed lateral ends of the sister piece; additionally they seal the ends against moisture, which can separate or loosen the fibers; and still further, such bands protect these ends to an extent against injury tending to split or open these edge portions.

A further reinforcement against separation of the fibers from the matte resides in applying a marginal stitching 13D close to the edges of the sister strip.

This marginal stitching may be run over any endwise banding 13C, or may be used where such banding is omitted with equal efiect on any paper boards of the class mentioned, and is especially effective on binders board or chip board to prevent opening up along the edges due to moisture or mechanical working in use, it being a characteristic of the latter two boards that if an excessive force is properly applied the binders or chip board can be split apart, tearing the pieces into two ragged layers leaving one piece of the original board held by the backbone glue and another held by the ring binder mechanism; and any edgewise opening-up of such matte boards tends to prepare for such cleavages when and if the excessive forces are applied. The lateral banding 13C and the marginal stitching 13D is applicable to binders which are to be subjected to extraordinary abuse.

It has been known in the art heretofore to bend the backbone board while in a wet condition and thereafter dry the pieces on a mandrel. Such expediencies reduce damage to the board but are costly and do not produce an inherently stronger backbone except indirectly in eliminating initial injury to the fibrous matte.

Composite backbones have also been proposed in various forms to include reinforcing means such as metal inserts between layers of pasteboard, leather, tarboard and like materials; most of these arrangements objectionably increase the thickness of the backbone and produce a bulky, gross appearance, and increase costs prohibitively.

There is some evidence that the greater strength of the herein described backbone arises in part from deforming the two backbone blanks separately so that the pieces take their initial and secondary shapes (after leaving the dies) before joinder; and it further appears that the coating of the convex side of the sister piece with glue subsequent to the formingup operation is of technical ad- 'vantage in that the glue is then applied to the surface in its deformed or mutilated condition, and hence to whatever exposed irregularities and ruptures exist at that time, so that when the two pre-formed pieces are pressed together the glue not only adheres to, and bonds with, the confronting SBTfECES bUlI rigidities and mends the weakened portions which it reaches, and which have been purposely adduced in advanced by the separate deforming operations, as distinguished from an operation in which the flat leaves are first supplied with glue and brought together and then subjected to deformation in the dies to take their shapes simultaneously with some initial strains which tend to change the bond as soon as the pieces leave the dies unless the assembly is allowed to remain in the die for full setting or drying of the glue under heat treatment.

Of equal commercial importance with the backbone structure is the blind or concealed rivet construction shown in Figs. 5 and 6, since it affords an inexpensive method of greatly improving the appearance of the binder by eliminating the passage of the rivet completely through the backbone and the unsightly rivet head in evidence on the outside, as in the old type ofbinder of this class.

In efiect, the head 17A of the rivet is gripped between the two bonded paperboard backbone pieces, and the radial grooves 16A (Fig. 3A and Fig. 5 adjoining the rivet holes serves as a concealed, bulkless reinforcing means to augment the bond between the backbone pieces themselves in this region and between the rivet head and the inner backbone or sister piece.

While binders board has been referred to specifically herein, it is intended that this designation shall be merely representative of one specific example of a type of paper board which is useful in the structure and the practice of the method. Another type of paperboard which may be successfully employed is known in the trade as chip board, and is usually more expensive. Chip board often has some paste or other binder admixed with the fibers, and splits and cracks much in the manner of binders board.

Still another type of board known in the bookbinding art may be successfully employed for the manufacture of the composite backbone structure, namely, tarboard; but boards of the latter class have a higher inherent strength, and the advantage offered by the present disclosures is mainly directed at paper boards which have little or no inherent rigidity, and a minimum of binding or cohesive bonding of fibers.

I claim:

1. A book casing comprising a pair of coverboards made from stock of predetermined thickness joined to an intervening backbone structure by a fabric hinge, said backbone structure comprising two superimposed strips of paperboard having an aggregate thickness substantially equal to said predetermined thickness of the coverboard stock and curved transversely to define a rounded type backbone, said strips being bonded into a condition of substantially rigid curvature as aforesaid, the longitudinal edges of the inner backbone strip projecting laterally beyond the corresponding underlying edges of the outer backbone strip so as to respectively abut one of the juxtaposed edges of the coverboards in closed condition of the latter.

2. The method of making a round-back book casing which comprises forming a flat case blank having a fiat backbone strip and a pair of flanking cover boards all hingedly joined by an outside cover cloth at least, said strip being made of matted paper board containing no additive agglutinants or stiffening agents and the strip being about half the thickness of the cover boards; curving said backbone strip in dry condition in the blank case; forming independently a curved sister backbone from said paper board in dry condition and having approximately the same thickness as the backbone strip; coating the convex side of the pre-formed sister backbone with a hard-setting glue of the class of hide glues, and pressing the glued side of the same home into nested interfit with the outer backbone until the glue is substantially set, whereby to form a substantially rigid composite backbone of matted paper board consisting of two independently curved pieces joined by the agglutinate applied after the curvature is imparted to the sister member, at least.

3. The method of fabricating round back binders from binders board, which comprises making a flat blank case consisting of a pair of cover boards flanking a first backbone strip of binders board, said covers and strip having adhered thereto a cloth outer cover hingedly joining the covers with said backbone strip, then rounding said strip; making a sister backbone strip and rounding the same separately to substantially the same curvature as said first backbone strip; fully coating the convex side of the sister li strip with a hard-setting gluezand pressing the same home into nested interfit against the concave side of said first strip and permitting the glue to set.

4. The method of fabricating a book structure of the round back variety from binders board, which comprises making a flat blank case consisting of a pair of cover boards of the same predetermined thickness, and an outer backbone strip of the same type of board but only approximately one-half the thickness of said cover boards, all hingedly joined by an outer cloth cover; rounding said outer. backbone strip; making an inner backbone strip of the same board and thickness as the outer strip, and separately rounding same to a curvature substantially complementary to that of the outer backbone; fully coating the convex surface of the inner backbone with a glue of the class including hide glues, and pressing the coated inner backbone into nested interfit with the inner surface of the outer backbone until the glue is dried.

5. The method of fabricating loose-leaf binders of the type having a rounded back with a binding device riveted thereto, which method comprises the following steps, to wit: making a flat case consisting of a pair of cover boards of predetermined thickness hingedly joined to a flat outer backbone strip of binders board having about one-half the thickness of said predetermined thickness; thereafter rounding said backbone strip to a predetermined curvature; forming with rivet punches a second backbone strip of substantially the same size material and thickness as said outer strip; separately rounding said second strip to approximately the same curvature as the outer strip; inserting headed rivets in said punches with their heads on the convex side of said second strip; thoroughly coating saidconvex side and the rivet heads thereon with a hardsetting glue, and pressing said second strip into nested interfit with the concave face of said outer strip until said glue has set, whereby to form a composite rounded backbone of binders board having substantially the same thickness as the cover boards with the rivet heads concealed and gripped between the outer and inner backbone pieces, said rivets being adapted to engage and hold a binder device as aforesaid.

6. In a round back book casing of the type comprising a pair of cover boards of identical thickness closely flanking a backbone strip, said covers and strip being joined to an'outside cover colth, at least, aifording a hinged juncture between each of the opposite longitudinal edges of the backbone strip and one of the adjoining longitudinal hinge edges of each cover board, improvements in a backbone structure comprising, to wit: a composite backbone consisting of two curved backbone strips of binders board each of about one-half the thickness of a cover board, said backbone strips being joined in nested interfit by a layer of-hard-setting glue therebetween, the longitudinal hinge edges of the innermost one of said backbone strips projecting beyond the corresponding underlying hinge margins of the outer trip an amount depending upon the spacing between the hinge margins of the cover boards from the hinge margins of the outer backbone strip, and suflicient to substantially abut said hinge margins of the coverboards When the latter are in substantially closed condition, that is to say, when the covers are in planes approximately normal to the plane containing the diameter of the curved backbone, whereby a load on the backbone acting toward the hinge margins of the covers in said closed condition tends to cause the projecting margins of the inner backbone'strip to bear upon the abutting hinge margins of the cover boards.

7. In a round back book casing of the type including a backbone adapted to have a binding device riveted thereto and which backbone is hingedly joined to a pair of flanking covers of similar predetermined thickness, an improved backbone structure including blind rivets for a binding device as aforesaid, said structure comprising, to wit: apairvof Icurved backbone pieces each of approximately one-half the thickness of said covers, said backbone pieces being joined in nested interfit by an intermediate layer of hard-setting glue, the inner backbone having rivet punches therethrough with headed rivets set therein with their heads disposed between the two backbone pieces.

8. A backbone structure according to claim 7 and further characterized in that said inner backbone piece has formed on the inside or convex side thereof a plurality Y of grooves each communicating radially into one of the (iii rivet punches, said grooves not being cut through the thickness of the piece but each having a bottom, said grooves being adapted to receive and retain a quantum of the glue which bonds the two backbone pieces where by to strengthen such bond in the region adjoining said punches and the rivet heads thereat.

9. A book casing having a rounded backbone structure and comprising a pair of paperboard covers of the same predetermined thickness flanking a composite backbone structure comprising a pair of superimposed paperboard strips each of about half the said predetermined thickness so as to aggregate in said superimposed condition the thickness of one of said coverboards, said strips being curved transversely and bonded together in said curved condition by an intervening layer of hard-setting glue to provide a substantially rigid composite backbone, the innermost one of said strips having its longitudinal edge portions projected beyond the corresponding margins of the underlying companion strip, and said composite backbone being flanked by said coverboards and hingedly joined to the latter by a pliable sheeting adhered to the outside surfaces thereof with a space between the confronting edges of said coverboards and said projecting longitudinal edge portions of the backbone structure; together with a liner of pliable sheeting adhered to inside surface portions of said backbone structure and adjoining portions of said coverboards and spanning said space between the latter and said projecting edge portions of the backbone and permanently depressed into the latter space, said projecting edge portions in relation to the remaining underlying edge portions of the companion strip in the backbone structure ailording a ledge space in which said depressed liner fabric can be accommodated in the closed condition of said book casing.

10. The method of making a book casing which cornprises forming a blank case including a flat main backbone strip flanked by a pair of covers, the latter being hingedly joined to the former, rounding said main strip to impart a lateral curvature thereto; separately rounding a sister backbone strip to corresponding curvature, superimposing the sister strip upon the inside of said main strip with an adhesive interposed; and setting the sister strip home into the main strip.

11. The method of claim 10 in which said strips are of equal initial lateral Width, at least, and said curvatures are such that When the sister strip is set home, as aforesaid, the resultant curvature is such that the longitudinal edges of the sister strip lie beyond the corresponding underlying edges of the main strip in closer relation to the respectively juxtaposed edges of said covers than are said underlying edges of the main strip.

12. In a book casing of the type having a pair of covers formed of stock of predetermined thickness joined by a pliable hinge to a backbone structure, improvements comprising: a rounded backbone consisting of a pair of strips each of lesser thickness than the cover stock and being curved laterally and adhesively conjoined in nested relation by an adhesive between the nested interfaces thereof the aggregate thickness of the backbone being not substantially greater than the thickness of a cover, that one of the strips which is inside the other having its opposite longitudinal edges projecting beyond the corresponding edges of the other strip to overhang the latter edges whereby to leave a cavity beneath the overhanging projecting parts of the strip along both hinge joints between the covers and backbone, said covers and backbone structure being hingedly joined by a pliable material joined to portions of the covers and the backbone at least in the region of said joints and attaching the covers sufiiciently close to said projecting edge portions to abut the latter in the closed condition of the covers with said overhanging edge portions afifording an elongated cavity along one side of each joint to provide a space into which a portion of the hinge material can be accommodated.

13. Construction according to claim 12 in which there are at least two thicknesses of said hinge material, one on the outside of the covers and backbone and one on 10 the inside thereof, and the two thicknesses along the hinge joint are pressed into conjunction and adhesively joined along a line paralleling the appertaining cavity.

References Cited in the file of this patent UNITED STATES PATENTS 343,439 Crane June 8, 1886 395,408 Sullivan Jan. 1, 1889 1,908,109 Bolton May 9, 1933 2,153,056 Cruzan May 16, 1939 2,486,330 Schade Oct. 25, 1949 

